Description (shell):Shell with tall, coeloconoidspire of seven tumidwhorls. Protoconch is rather bulbous, last whorl about 70-80 % of shell height. Sutures are shallow, slightly accentuated by a narrow subsutural ridge, more conspicuous on last whorl where it is seen to derive from anal sinus. Periostracum is thin, often lost in older shells. Sculpture of numerous, fine spiral striae and flexuous growth lines. A thick spiral keel, the siphonal fasciole, runs from shell base to umbilical region. Aperture is broadly oval or egg-shaped, pointed adapically, with small anal sinus; basally a short, broad siphonal canal (N. antiqua-drawing).

Size:Commonly up to 200 x50 mm, occasionally up to twice this size.

Colour:Yellowish, sometimes with reddish tinge, throat usually more heavily pigmented.

Animal:Cephalic tentacles are long, distal half slender, eyes at junction with broader basal portion. Siphon does not project far from canal in active animals. Foot is large, with double-edged anterior margin and small anterio-lateral horns; females with opening of ventralpedal gland on sole. Operculum is oval, pointed adapically, with a terminal nucleus.

Habitat:Sublittoral, from 15-1200 m;mainly on soft substrata.

Distribution:Widely distributed from Biscay to Arctic; found in the whole North Sea (Distr. N. antiqua).